Towed vehicles, such as trailers, have brake signals that operate based on the braking signals of the towing vehicle. As is well known in the art, the braking signals of the towing vehicle are electrically connected to the braking system of the towed vehicle, such as via an electrical adapter, or the like. Typically, the signaling system of the towing vehicle has a signal lamp and a brake lamp that are operated by at least two separate filaments. However, most trailer signal systems usually combine the turn and brake signals into a single lamp with a single filament. Accordingly, an adapter or circuitry is required in order to interface the signal system of the towing vehicle with the signal system of the towed vehicle or trailer.
Adapters that interface the signaling system of the towing vehicle and their respective towed vehicle or trailer are well known. Most adapters use the power from the signal system of the towing vehicle to power the signaling system of the towed vehicle. In order to accomplish this, the adapter must increase the amount of current from the towing vehicle signaling system to the towed vehicle signaling system. However, there are many disadvantages to such adapters.
One such disadvantage of known converters is that they do not have adequate safety and back-up features. For example, traditional converters typically do not have adequate overload and short circuit protection. As a result, traditional converters present a risk due to overheating should the load on the output exceed the rated load. Frequently, towed vehicles or trailers may have marking lights added to the taillights, for example, that may further increase the load on the output of the tail channel of the signaling system and, thus, the probability of exceeding the rated load of the output is quite possible. Traditional converters that have a means to detect short circuits may not have an automatic reset function wherein upon removal of the short circuit the converter starts normal operation.
Moreover, known adapters or converters fail to adequately protect the adapter if the load at the output exceeds the ratings of the converter. The failed attempts of known converters involve implementing thermal protection on the output driver. However, the thermal protection of the converter is a remedial measure. Thermal protection does not prevent the potential or eventual problem that causes overheating. Additionally, these known converters fail to detect short circuits and, as a result, can be damaged due to short circuit conditions.
Devices have also been developed that illuminate the signaling system of the towed vehicle with power signals separate from the towing vehicle signaling system. For example, solid state switching devices, such as transistors, relay coils, or other types of signal detection devices, may be used. However, these devices also have many disadvantages. For example, these devices can be damaged due to high power dissipation such as caused by high currents during overload or short circuit.
The towing vehicles may use a single bulb to indicate STOPLIGHT and TAILLIGHT functions. This is done by driving the light continuously for STOPLIGHT and for a partial time for TAILLIGHT. When a towed vehicle with known converters is connected to such towing vehicles, the TAILLIGHT may not function properly, may be very dim or flash.
Thus, the known converters are not capable of driving the lighting system of a towed vehicle to indicate a combined STOPLIGHT and TAILLIGHT bulb or light system. In addition, the prior art utilizes “smart drivers” that integrate all functions of a charge pump, current sense, temperature sense, or combinations thereof onto a single die. That makes the cost of these “smart drivers” very expensive. Not to mention that the consumer must take these drivers with all of the manufacturers specifications without a choice or any options. If the functions were separated, they could be tailored or fine tuned by the consumer for the specific application they were purchased for.
Therefore, there is a need in the art for an improved trailer signal converter or adapter. The present invention seeks to overcome many of the shortcomings of known adapters and circuitry for connecting the signaling system of the towing vehicle with the signaling system of the towed vehicle.